Compensating apparatus for contour turning



Feb. 6, 1945. I D w|LsON 2,368,793

COMPENSATING APPARATUS FOR CONTOUR TURNING Filed July 2o, 1942 5 sheets-sheet 1 ATTORNEY;

D. l. WILSON Feb. 6, 1945.

COMPENSATING APPARATUS FOR CONTOUR lTURNING Filed July 20, 1942 5 sheets-sheet 2 .N d1 l Juve/nm DILBERT 1', WILSQN Feb. 6,1945. D. WILSON COMPENSATING APPARATUS FOR CONTOUR TURNING 3 Sheets-Sheet 3 .Filed July 20, 1942 BY f Patented Feb. 6, 1945 UNITED `STATES J PA'IflZNT OFFICE y f Y,2,368,793

ooMPENsATrNG APPARATUS FoRooNTo'UR TURNING Delbert I. Wilson, Dayton, ohio, assignor yto The City Engineering Company, Dayton, Ohio, a

, corporation of Ohio Application july 2,0, i942, serialNo. 451,567

o clame., (o1. 8252s).

the motion is transmitted 'through a 'lever system.`

In machines of various types it is conventional to actuate different mechanisms by means of a cam whose surface is engaged by one end of a lever so that rotation of the cam produces movement of a device adapted to be actuated` by 'the lever. Such mechanisms haveparticular use on screw machines wherein cams are mounted upon a cam shaft and are adapted to be engaged vby one end of a lever, the opposite end of the lever engaging a mechanism to move the turning tools, or to move the spindle of the machine for l'feeding the stock adjacent the tools. n Whenthelever is rotated upon its pivot, the end lthereof that engages the surface of the cam-swings in an arc about the pivot for the lever and thereby introduces an error Sinto the movement ,of .the lever which can only be cured by providing a specially ground surface ontheface ofthe cam. V'The cam cannot be precalculated and ground to the shape determined mathematically `but rather the cam must be rst produced mathematically and then reground by a trial and error process to correct the error produced by the arcuate movement of the lever that engages the cam surface.

An object of the invention isto vprovide an arrangement of a cam and lever .system that avoids al1 error in the movement of the lever due to the arcuate travel of the end of the lever for transmitting the .motion of the cam toa driven device.l Another object of the invention is to provide acam and lever system for producing motion of a device wherein the means vengaging the cam in the lever system moves in astraight line even though the end of the lever that picks up the motion of the cam moves yin an arc, whereby error produced by thearcuatemovement of .the endof the leveris eliminated.

Another object of thev inventionis .toprovide a screw mahine vwithajcam and lever system for feeding the stock through "the screw machine eliminate errors in the feeding ofthe "stock duel wherein the lever system 'is 'providedwith a 'compensating device `f or 'engaging 4the cam that produces the feeding movement 'of the stock to to arcuate movements vof 'the levers in the lever system.

Another object ofthe invention is to provide a machine wherein longitudinal movement of la device is controlled by means of'a cam that 'produces motion in va lever system for moving the device, and wherein meansmis provided 'between the cam and the lever 'system 'for compensating error developed` by the lever system due to the A arcuate yrriovemen't ofthe end of thev lever that receives its motion 'froinjthesurface of the cam.

AnotherY object 'of the ginvention is to provide an apparatus whereina portion of 'the apparatus is controlled .in longitudinal movement by means Y of a cam which transmits motion .through a lever system,` .and wherein ya cam follower is disposed between the cam and the flever system to prevent f error in 'the )movement of lthe longitudinally driven portion as caused bythe arcuate movement of alever lin engagement with the surface of the cam.

Another object of the invention is to ,provide an apparatus 'wherein longitudinalinovement o'f a portion of the apparatus is produced bymeans of a lever system as actuated lby means .of ajcam and a cam follower is disposed-between the cam and vthe lever -system (in alman'ner that the follower moves `in aislar/aight line to eliminate errors that would normally be transmitted through the lever system if the end thereof .engages 'the Acam and follows its normal arcuate path while Yin engagement withthe cam.

Another object of the invention is to provide a machine wherein ylongtud'inal 'motion is'producedin a portion of the' machine by means of a lever vsystem that receives its motion from a cam,- and wherein the lever system is constructed and arranged 'in a manner Athata lcam vhaving a` precalculated contour can be placed on themachine and the lever system will accurately transfer the dimensions calculated to lbe produced lby the cam upon aworkpiece.

Another/object of the inventi'onis to provide to be moved longitudinally for feeding stock that is operated by a cam and lever system and arranged in accordance with any of the foregoing objects.

Further objects and advantages will become apparent from the drawings and the followin description.

In the drawings:

Fig. 1 is a side elevational View, partly in crosssecton, of a screw machine incorporating features of thisinvention.

Fig. 2 is an elevational view of a portion of the screw machine of Fig. l showing the mechanism for longitudinally moving the spindle of a screw machine for feeding stock past the turning tools. y

Fig. 3 is an'end elevational view of the screw machine taken along line 3-3 of Fig. 1 sho-wing the cam and lever system of this invention.

Fig. 4 is an elevational view, partly in crosssection, showing theturning tools and the cam means for operating the same.

Fig. 5 is a crosssectional View taken along line 5-5 of Fig. 3.

Fig. 6 is a horizontal cross-sectional View taken alongline 6-6 of Fig. 3.

Fig. '7 is a vertical cross-sectional view taken along line 'l-l of Fig. 6.

Fig. 8 is an elevational view of a workpiece that can be produced by the apparatus of this invention.v

In machine tools of various kind, some of the mechanisms are actuated by means of a pivoted lever that is engaged on vone end by a cam to produce motion 'in the opposite end of the lever and thereby operate a mechanism of the machine. The cam, of course, rotates upon a xed center or upon a cam shaft. A fixed point on the lever is adapted. to engage the surface of the cam and since the lever is pivoted the fixed point on the lever will travel in an arc .about the pivot center of the lever. This arcuate movement of the cam followerlor Xed point on the lever causes the point of contact of the cam follower with the cam to change toward the pivot center of the lever as the lever rotates about its pivot center, If .a cam is produced having a precalculated contour for producing a predetermined movement of amechanism of the machine, this' change in thecontact point of the Icam follower upon the cam surface produces a variation in` the movement transmitted to the lever that is not desirable, since it is necessary to rework the cam to eliminate the error, and this can only be done lby a trial and error process and the production of products on the machine to determine the actual effect of the cam upon the operation of the machine. 4Such errors are particularly noticeable when it is desired to produce an article having a tapered surface or some other special contour, it being necessary to rework the cam from its precalculated contour by a careful grinding of the surface until the desired effect is produced 'upon the lever actuatedby the cam to produce the desired taper or special contour.

All of this trial and error in the manufacture of cams, and the error in the lever system operated by the cam, can be overcome if the point of contact of the cam follower upon the cam is always in the same radial position upon the cam, that is the point of contact of the cam'follower must move in a straight line radially from the center of rotation of the cam.

There are many movements of levers produced by cams that can havetheiroperation improved Mof stock is very accurately maintained and the cam for producing the dimensions can be mathematically 'calculated for its contour without any possibility of error being transmitted through the lever system.

In this invention the apparatus is applied upon ascrew machine III having a base I I that supports a' main machine frame I2, The machine frame I2 supports a spindle I3 that is provided with a Vdovetail guide III adapted to slide in a dove'- tail guideway I5 provided in the frame I2. The spindle. I3 is adapted to receive the work stock I6 and to riction'ally engage the same so that movement of the spindle I3 longitudinally in the guideway I5 will feed the work stock I6 through a work stock guide bushing I'I carried in the guide bushingsupport I8.

'The base II support-san ,electric motor I9 that is directly connected to a speed'change device 20 for controlling the speed of the drive shaft 2l. Asuitable hand control member 22 is provided for regulating the operation of the speed changer 29. A flat pulley 23 is keyed to the drive shaft ZI and drives a belt 24 that engages the spindle I3 for driving the same and thus for rotating the work stock I6. y

The turning tools 25 and 25, see Fig. 4, are sup- -ported in tool holders'2'l vand 28, respectively, that are carried upon a rocker arm 29 pivoted upon the pin 3D that extends from the guide bushing support I8. The tool holder 28 is provided with a' micrometer adjustment 3| for regulating the position of the cuttinge'dge of the tool 26 transversely with respect to the work stock I6. A similar micrometer adjustmentis provided for longitudinally adjusting the tool support 28 to move the turning tool ZG'longitudinally with respect to the w-ork stock I'B and thereby adjust its position with regard to the turning tool 25. Similar micrometer adjustments may also be provided for the toolholder 21, thereby regulatingr the transverse and longitudinal positions of the turning tools 25 and 26 with regardto each other and with regard to the work stock I6. While there has been shown only two turning tools in this invention it is to be understood that the disclosure is merely representative of a screw machine and that other turning tools can be provided that work from different angles radially from the workpiece for producing various turning operations upon the work stock I6 and can be operated from cams carried upon a cam shaft hereinafter described.' The turning tools 25 ,andV 26 engage the work stock I6 rby a transverse movement as produced by a rocking motion of the rocker ,arm 29 about the pivot 3l! caused by a cam 32 secured to a cam shaft 33'and engaged by a'cam follower 34 that is secured to the rocker ar-m 29; The contour of the cam 32 controls the variousdepth cuts to be made upon the work stock It and determines which turning tool 25 or 26 will engage thework stock to produce the various'turning operations.

4'Ihe cam shaft 33 is' suitably bearinged upon the frame I2, one of such bearings being shown aeesymo at E35. .The :cam shaft 33 also carries :a y'worm wheel136 .driven .byfa -vvorm A3,1 carried upon-aa shaft l38 vthat 'supports .a m.pulley Y-39 `driven by a belt 40 .extending from `a driving pulley l4| V,carried upon -the 'shaft 42 of a speed change :device 43 driven by `an electric motor 44. The speed change device '43 is regulated-by means -of the manually operated .control handle :45 for thus controlling the speed of rotation'of the cam shaft 33 4and thus controlling the v.operation aof the :cam 32 'for 4regulating 4the speed of transverse movement of the turningtools -25 .and 26 with respect to the work stock I6.

The longitudinal movement :of the .spindle 'I3 is controlled by :means of a cam N|) carried upon the cam shaft33. The'cam 50 is engaged by :a cam follower 5|, see Fig. ,3, 4carried by a lever 52 that engages a bell crank lever53 for longitudinally moving the spindle |3.

The lever 52 Iis vpivoted. Yupon .a :pin 54 thatis carried upon a support bracket-55 secured tothe machine frame I 2 by means of the bolts1or screws 56. One end of the lever 52 carries Va roller 51 that engages a roller 58 carried upon one end of the bell crank ylever I53 that is pivoted to the machine frame |2 by means of a `pin 59 `carried in a bracket .60.

The opposite end of the lever 52 carries :a shoe 6I that is bearinged-in the lever 52 by-means of the shank 62 provided on the shoe 6|. The shank V62 can freely rotate Within :the bearing bore provided in the lever 52 and thereby permit rotation of the shoe 6|. Theshoe 16| is disposed in aguideway 63 providedin a slide .64 Awhereby the shoe 6| canmove transversely in the slide 64,.

The slide 64 is provided withguideways 65 and 66 that receive guide tracks 61 .and68, respectively, the guide tracks 61 "and 68 being-secured to themachine frame |2by means of theebolts or screws 69 and 10, respectively. The cam follower 5I is secured `to the slide 464 by means of the bolt or screw 1.|. The` cam follower 5| .lis provided with a hardened wear plate 12 thatv engages the surface of the cam 50. y

Theguide tracks 61 and 68 -control the rmovement of the slide 64 and thus the movement of the cam follower 5| in-a straight line. of movement of the cam follower .5| is -in a straight line radially from the center of rotation ofthe cam 50 so that regardless of the degree of movement of .the cam -follower 5| the point of contact of the follower withtlie surface of the cam 50 willalways be in the same relative position radially from the center of rotation of the cam 50. Therefore, .when a surface is generated upon the cam 50 lhaving a prede--` termined rise for `a .particular number ofdegrees of rotation of the cam, the lmovementof the cam .follower can be accurately predicted or precalculated. Movement ofthe slide 64 radially from the center of rotation of the cam -50 causes movement of -theshoe .6| radially from the c enter of rotation of the `cam 5|) so that the end of the lever 52 engaged by the shoe A6| .will be moved accordingly. However, since the shank 62 of the shoe 6|,.is rotatably carried in thelever. 52, the shoe can rotate with respect to the end of the lever 52, and since the endof the lever 52 moves in an arc about the pivot center 54, the shoe will move transversely Within the slide 64. This movement of the shoeis lin a straight line transverselyof the slide 64and therefore the degree of motiongiventhe lever .52 by the slide |54 through .the shoe .6| .will always be the ,same regardless `of the ...arcuate .swing of .the shank-.62

The lineoffithefshoe 6|.. mitting movements between the cam 5,0 and the lever -.52 are straight )line movements, there will be no' error in the .degree of motion transmitted `to the lever r52 :from the rise in theam 5 0.. Since the error .of motion transmiSSOD 132.0

the lever 52 has been -avoided .,the;contour of the cam 50 can .be `precalculated 31716. .ground tto e predetermined accuracy .so that when `the cam 50 is placed upon .the cam shaft `3,3 `a predetermined fand precalculated movementl of the lever 52 will be produced ,for transmission to the bell crank lever 53 and thus to the Yspindle .|3. The arm .13 .of the bell crank lever 53 is provided rwith a `slot 14 that receives a @Slide Amember l15 `carry.- ing an vantifrictionmember 16 such .as ia ball bearing that Aengages a-wearplate 11 vc arriedfupon an arm 18 extending transverselygfromhthe:Aspinf dle I3. sition upon the .slide 15 v.while a washer 80 and the nut 8| .secures the fslide in position within the slot 14 in the 311m 13 of the bellcrank lever 53. The slide 15 receives a `threaded rod 82 in threaded engagement therewith for ymoving the slide 15 longitudinally `Within. the rslot 14 tand thereby adjusting the eiective length of the bell crank arm 53, sincethe point of contact `of lthe ball bearing 16 upon the wear plate 11 `determines the effective length of the lever jarm,.13. The threaded rod 82has a shoulder 8.3 rotatably disposed within the end of the lever arm 13ar`1d retained therein `by means of Aa nut.84. A,knurled head 85 is secured to Ithe end of themed-821m provide -,means for rotating .the vsame .when adjusting the position of the slide 15.

Rotation of the leverfn as caused-bytheeam Eiland the .cam follower 5| will produce Vrotation of the bell crank` lever 53 `about the .pivot 59 thereby causing the ball bearing 16.to engage the wear plate 11 carried bythe spindle I3 v`to move the spindle longitudinally within the guide` way I5 for feeding the work stock Hipastl the turning tools25 and26. Suitable means suchas plate 11 in engagement withthe-ball bearing. 1.6

so that the movement ofthe Ibell crank lever 53 will vbe `accurately transmitted to the yspindlewl3. From the foregoingdescription it -will be Vap parent that all of the motion transmitted Afrom thecam;50 .to the4 spindle k|3 are in-effectstraght line movements so that any error produced .by arcuatefmovements is avoided. The arrangement thus .permits a very accurate Vcontrolover the lengthof the longitudinal turning operationsgas produced by movement of Vthespinclle |-3 with respect to the turning tools 25and v26, thespindle |3, of ycourse,-earrying the work stockl pastthe turningtools in its forward travel. The arrangement of the apparatus is particu larly advantageous -when turning special :contours, such astaperS, yradii .and others-on a completely automatic machine-,such -as standard automaticfscrew machines. Y'Accurate control over the transverse movement of' the turning toch l as well as accurate control overthe feedingof` y the `Work `stock pastthe turningitool lis-required when turning tapers on a workpiece, orlother special contours, since it fisrthe relationshippfl forward movement of the work stock and t-he transverse movement `of Athe turning ytook-that controls the shape of the contoun `jIhe-.feeding since au of the motion A nut 19 secures the ball vbearing v in Ipowork stock i6.

system heretofore referred to. If a predetei'fmined rise was required to produce a predeter- .mined forward motion of the spindle and thus of the work stock past the turning tools, it was not possibletolay out a cam mathematically and rknow the result on the iinal workpiece, Abecause rise on the cam will produce aprecalculated* movement of the lever regardless the position o-f the lever so that the relationship between-transverse movement of the turning tool and longitudinal movement of the spindle and work stock can be precalculated to produce a special contour upon the surface oftheworkpiece.

ASuch a workpiece is shown in Fig. 8 whe-rein a tapered portion 8B is being turned upon the The work stock It is moving in the direction of the arrow thereon, and therefore it becomes necessary to coordinate the transverse movement of the turning tool 25 with respect to the axial movement of the work stock i6 to produce the taper on the tapered portion 86.

While the apparatus ofthis invention has been described in an association with a particular type of machine, yet it is to be understood that the mechanism is capable of being used on any other machine wherein it is desired to accurately control the transmission of a rise on a cam to a lever' system for transmitting the movement to the movable apparatus on the machine, and while the apparatus disclosed herein shows and describes a preferred form of the invention, that the apparatus is capable of mechanical alteration Withou|t departing from the spirit of the invention, and that all such modifications of the apparatus as fall Iwithin the scope of the appended claims are intended to 'be included herein.

Having thus fully described my invention, what I claim as new and desire to secure by Letters Patent, is:

l. In a motion transmitting system, the combination of, a cam, a pivoted lever for receiving motion from said cam and adapted to transmit the motion, means engaged |by said cam and movable in a straight line radially from said cam, means carried by said rst mentioned means and movable thereon in a straight line normal to the straight line movement of the said first means for connecting the same to said lever for accurately transmitting the motion from a` predetermined cam rise to said lever.

2. In a motion transmitting system, the combination of, a cam adapted to be rotated, a lever` pivotally mounted adjacent said cam, a cam follower, guide means for said camv follower for directing the motion thereof in a straight line radially from said cam, a recess in Said follower disposed normal to the straight line motion of said follower, a slide shoe carried upon said follower in said recess and movable at a right angle to the direction of movement of said cam follower, and means connecting said shoe to said lever, whereby a predetermined rise on said cam is accurately transmitted to said lever.

- 3. In a machine tool, the combination of, a

mechanism adapted to have motion imparted thereto, a lever system for imparting motion to said mechanism, cam means for producing motion in said lever system, means disposed between said cam and said lever system for .continuously engaging said cam in a single plane extending radially from said cam, and means connecting said last mentioned means to said lever system to transfer the straight line motion therein to the arcuate movement of a lever of said lever system, whereby a predetermined rise on said cam is accurately transferred to said lever system.

4. In a screw machine, the combination of, a spindle adapted to be moved axially for feeding work stock past the turning tools of the screw machine, a lever system for producing axial movement of said spindle, cam means for producing movement in said lever system, one of the levers in said system having an end thereof adjacent said cam movable in an arcuate path and adapted to receive motion imparted thereto from said cam, and means carried by said lever and movable in a straight line radially from Said cam for transmitting the straight line motion of the cam engaging means to said end of said lever,

whereby a predetermined rise on said cam is accurately transmitted to said end'of said lever and thus through said lever system to said spindle.

5. In a screw machine, the combination of, a spindle movable axially for feeding work stock past the turning too-1s of the screw machine, rotatable cam means for producing movement of said spindle, a lever system interposed between said cam means and said spindle to move the spindle upon rotation of the cam means, one of the levers in said system having an end thereof adjacent said cam movable in an arcuate path and adapted t0 receive motion imparted thereto directly from said cam, and a cam follower carried by said end of the lever and having means guiding the same in a straight line radially from said cam and including means for transmitting the straight line motion of said follower to said end of said lever for accurately transmitting a predetermined cam risel to said end of said lever to move said spindle a, determined amount.

6. In a screw machine, the'combination of, a

spindle movable axially for feeding work stock past the turning tools of the screw machine, ro

tatable cam means for producing movement of said spindle, a lever system interposed between said cam means and said spindle to move the spindle upon rotation of the cam means, one of the levers in said system having an end thereof adjacent said cam movable in an arcuate path and adapted to receive motion imparted thereto from said cam, a cam follower supported entirely from said end of the lever, means for guiding said follower in a straight line motion radially from said cam, a shoe carried by said end of said lever supporting said follower and movable at a right angle to the movement of said follower to transmit the straight line motion 'of said follower to said end of said lever for accurately transferring a predetermined rise on said cam to said end of said lever.

7. In a screw machine, the combination of a spindle movable axially for. feeding the work stock past the turning tools of the screw machine, rotatable cam means for producing movement of said spindle, a lever system interposed between said cam means ,and Vsaid Vsp-indle to move the spindle upon rotation of the cam means,

one of the levers in said ysystem having an end thereof adjacent said cam movable in an arcuate path and adapted to receive motion imparted thereto directly from said cam, acam follower V arranged to engage the periphery of said cam carried by the end of said lever and having means guiding the same in a straight vline radially from said cam, and a shoe pivotally oonnected with the end of said lever and guided for movements in said follower transversely of the lin in which said follower moves, said parts constructed and arranged for transmitting the straight line motion of said follower to said end V n of said lever for accurately transmitting a predetermined cam rise to said end ofsaid lever to n move said spindlea determined amount.

8. A motion transmitting system for a screw machine that has a spindle movable axially relative to Work tools upon the screw machine and a cam shaft that carries cam members for procam follower for movement at a right angle`rel.

ative to the movement of the cam follower, and

a lever system interposed between said cam and l the spindle of the screw machine operably connected to said shoe to receive and transmit momachine accurately for each predetermined .rise onlthe cam. fl

9. A motion transmitting `system for a-screw `machine that has a spindle movableaxially rel-V ative to work tools upon the screw machine and a .cam shaft that carries cam members forpro- 5 ducing` Work movement of the tools .and axial movement of the spindlewherein the cam shaft Y extends longitudinally adjacent the spindle of the screw machine and includes in combination, a cam carried by the cam shaft ofthe machine for causing axial movement ofthe spindle,` a'cam A y follower engaging the periphery of said cam for movement thereby, guide means on the machine I for guiding said follower in a straight linefmotion radially from said 'cam and normal' to the axis of rotation thereof, a: lever pivotally mounted adjacent said cam, a shoe'movable in and carried byl said follower for movement normal to the line of movement 'of said follower and having means engaging one end of said lever to transmit motion to said end of said lever,-a second lever pivotally mounted on said machine for oscillation angularly to the oscillating movement of the first lever means and having means' eny gaging the rst levermeans to receive motion therefrom as imparted thereto upon a straight' surface to establish a straight line movement between the two lever means, and means carried by said second lever means for operably engaging said spindle of the machine and imparting thereto movement by straight line motion between the said means and the spindle of the machine.

DELBERT I. WILSON-` l tion from said cam to the spindle of the screw n 

